They may both be Kryptonian but that doesn't make them equal in strength and muscle. Cavill/Superman is bigger and more muscular guy than Shannon/Zod and that has to count for something.
That's what I see too. Nothing in the trailers suggests that he's emo as a man, just unrooted and looking for purpose. Even as a loner vagrant, he looks stalwart and self-assured. When he is younger, sure he seems a bit emotional.